"Last Resort," ABC's new thriller set aboard a Navy ballistic missile submarine, leaves you gasping for air within the first few minutes of its pre-deployment shakedown cruise.

The show's pilot, available online now before its prime-time TV premiere Sept. 27, feels more like a nuclear-tipped roller-coaster ride for all of its plot twists and explosive turns.

Co-created by Shawn Ryan — producer of "The Shield," "Lie to Me" and "The Unit" — the show stars "Homicide" Emmy-winner and "Glory" veteran Andre Braugher as Capt. Marcus Chaplin, skipper of the Colorado.

His big-screen Civil War experience may come in handy, as the show wastes no time delving into the issues of a country at war with itself. Indeed, the show's tag line is "U.S. vs. Us."

With real-world pundits and politicians saying the country hasn't been this divided since the Civil War, the show navigates the strategic what-ifs of a military breakaway alongside the tactical tight corners of disobeying unlawful orders.

" ‘Last Resort' is really uncharted territory," Braugher says in a promotional video. "Everything that happens is new and unexplored and absolutely fascinating."

The first episode launches with a covert SEAL team pickup in the Indian Ocean and dives into the action from there. Within 10 minutes, there's intrigue in Washington, whispered mysteries among the SEALs, the crew dancing to "La Bamba" as the boat crosses the equator, and a call to battle stations with questionable orders to fire a salvo of nuclear missiles at Pakistan.

Writers even manage to poke fun at Navy "sensitivity training" with a laugh-out-loud joke about a female shipmate's "rack."

"I liked it. I couldn't turn it off," says retired Navy Cmdr. Fred Borgmann, who spent his entire 34-year career aboard subs and is now the executive administrator of United States Submarine Veterans in Silverdale, Wash. "I have a son who was in the SEALs for 20-some years, so I could relate to both sets of characters — the submariners and the SEALs," Borgmann says. "Some of it is kind of far out — you can nitpick the hell out of it, if you want to — but I thought it was pretty intense and very well done. It had me hooked. I'd recommend it to anyone."

Although there is no real-life Ohio-class sub named the Colorado, the fictional warship shares the same 753 hull number as the smaller Los Angeles-class attack submarine Albany, based in Norfolk, Va.

The first real Colorado was a Union frigate, and the last to bear the state's name was a World War II battleship. But in April, the Navy announced the name would resurface among the next subs built in its Virginia-class attack boats.

Unlike the Hollywood embed that created "Act of Valor" — also featuring SEALs and subs — the Navy did not provide support for "Last Resort."

And apparently producers didn't ask.

"They did not come to us for help," said Lt. Cmdr. Paul Macapagal, a Navy spokesman at the Pentagon.

That's not surprising, given the show's edge. And anyone who's served aboard a boomer, as the Navy's biggest subs are known, will have to make room for a deluge of "that-could-never-happen" moments.

But the show's willingness to push the envelope also could make it a draw to military and civilians alike.